Electro-magnetic pump



Filed July 15, 1954 6, 1957 L. c. PARKER 2,801,591

ELECTED-MAGNETIC PUMP 2 Sheets-Sheet l Hill-l Vac INVENTOR- oceland'fialjier' ATTOBNEY WITNESS 6, 1957 L. c. PARKER 2,801,591

ELECTRO-MAGNETIC PUMP Filed July 15, 1954 Sheets-Sheet 2 110 Vac 0T 5 jz Q INVENTOR. WITNESS:

ZZZIZQZZZQ WM TORN E Y 2,801,591 Patented Aug. 6, 1957 ELECTRO-MAGNETICPUMP Leland C. Parker, Elmira, N. Y., assignor to Bendix AviationCorporation, a corporation of Delaware Application July 15, 1954, SerialNo. 443,529

6 Claims. (Cl. 103-38) The present invention relates to anelectro-magnetic pump and more particularly to a reciprocating pumpadapted for operation by pulsating direct current to maintain anapproximately constant level or head throughout a wide range of outputvolume.

It is an object of the present invention to provide a novel pump of theabove character which is simple and economical in construction andefiicient and reliable in operation.

It is another object to provide such a device having no moving contactsor other current carrying devices subject to arcing or pitting.

It is another object to provide such a device in which the control ofoutput volume is secured by regulation of the length of stroke of thepiston while its frequency is maintained constant.

Further objects and advantages will be apparentfrom the followingdescription taken in connection with the accompanying drawing in which:

Fig. 1 is a vertical substantially mid-sectional view of a preferredembodiment of theinvention adapted to main tain a substantially constantlevel of the liquid being pumped, the electrical circuit being indicateddiagrammatically; and

Fig. 2 is a similar view of an embodiment of the invention which isarranged to maintain a constant output pressure of the liquid beingpumped.

In Fig. 1 of the drawing there is illustrated a non-magnetic cylinder 1in which is slidably mounted a hollow magnetic piston 2. Anelectro-magnet 3 is arranged to surround the cylinder and piston, andthe assembly is mounted coaxially in a cylindrical casing 4 of magneticmaterial by means of annular pole pieces 5 and 6 located at the oppositeends of the electro-magnet. I

Means for energizing the electro-magnet 3 is provided comprising leads 7and 8 connected to a source of alternating current such as theconventional 110 volt 60 cycle commercial power supply. In one of theleads a rectifier 9 is inserted whereby the electro magnet is suppliedwith pulsating direct current and is consequently activated periodicallywithout change of polarity at the frequency of the alternating powersupply.

The lower end of the casing 4 is extended to provide an inlet chamber 11having an inlet fitting 12 and closed by a cap 13 of any suitableconstruction. The lower end of the cylinder 1 extends into the inletchamber 11 and is threaded to receive a hollow externally threadednipple 14 in the bottom of which an inwardly opening check valve 15 ismounted. The upper end of the nipple 14 forms an abutment for the piston2, limiting its movement away from centered relation with respect to theelectro-magnet 3.

A check valve 16 is mounted in the lower end of the piston 20 to preventbackward flow of liquid, whereby reciprocation of the piston drawsliquid from the input chamber 11 and pumps it through the cylinder 1.

A cylindrical housing 17 forming the output chamber of the pump issuitably fixed to the upper end of the cas- 2 ing 4, andis provided witha sealed connection to the upper end of the cylinder 1 as indicated at18. The output chamber is provided with an outlet fitting 19, and anoverflow connection 21, and is closed by a cap 22 suit ably aflixedthereto as indicated at 23.

A hollow float member 24 is located in the output chamber 17 and restson a compression spring 25 which is seated on the upper end of thepiston 2 and consequently urges the piston away from its centeredrelation with the electro-magnet 3, toward the input chamber 11.

Yielding means for varying the pressure of the spring 25 on the piston 2is provided in the form of a spring 26 bearing on the upper side of thefloat 24 with a pressure which is adjustable by means of an anchoringstud 27 threaded through the cap 22 and maintained in adjusted positionby a lock nut 28.

In use, it is intended that the pump maintain a constant level of liquidin the output chamber such as indicated by the line 29, with littlevariation throughout When the power is first ap-.

the range of output volume. plied to the pump, if the liquid in theoutput chamber 17 is below the desired level, the weight of the float 24plus the force of the adjusting spring 26 is applied to the piston 2through the spring 25 whereby the piston is moved to a substantiallydecentered relation with respect to the electro-magnet 3 during theinterval between each periodic energization of the electro-magnet. Thepiston therefore is caused to vibrate throughout substantially its fullstroke as limited by its engagement with the nipple 14.

Liquid is consequently pumped rapidly into the output chamber 17,causing the liquid to rise toward the desired level 29. The buoyancy ofthe float 24 is thus caused to relieve the pressure on the spring 25until, when the desired level 29 is reached, there is little or nopressure on the piston and its decentering movement between the pulsesof the electro-rnagnet 3 is insufficient to operate the check valves 15,16 so that no further liquid is pumped.

Thereafter, as liquid is drawn off through the output fitting 19, it isconstantly and immediately replaced by the pump, the stroke of whichautomatically conforms to the volume of liquid being drawn from theoutput chamber.

Any desired adjustment of the height of the liquid level in the outputchamber is secured by adjustment of the pressure on spring 26. Theoverflow fitting 21 is provided merely as a factor of safety.

In the embodiment of the invention illustrated in Fig. 2, the operativeelements of the pump are the same as shown in Fig. 1 and are similarlynumbered. In this case however, instead of maintaining a constant levelof liquid in the output chamber it is intended to maintain a constantoutput pressure.

For this purpose, the output chamber 31 of the pump is closed by aflexible diaphragm 32 which is mounted thereon by means of a cap 33suitably aflixed to the upper end of the pump casing as indicated at 34.

The center of the diaphragm 32 bears on a spring 35 which is seated onthe upper end of the piston 2, a thimble 36 being preferably interposedtherebetween. Yielding means for applying pressure to the diaphragm 32is provided in the form of a compression spring 37 hearing on thediaphragm and seated at its upper end in a thimble 38 mounted on a stud39 threaded within a sleeve 41 fixed in the cap 33. Adjustment of thestud 39 consequently varies the pressure applied through the spring 35to urge the piston 2 away from its centered position with respect toelectro-magnet 3, toward the input chamber 11.

In the operation of this embodiment of the invention, application ofpulsating power to the electro-magnet 3 causes the piston 2 to bereciprocated through substan tially its full stroke, whereby liquid ispumped into the output chamber 31, developing pressure on the under sideof the diaphragm 32 tending to move it upwardly against the force of thespring 37, thereby relieving the pressure of the spring 35 on the piston2.

When the desired amount of output pressure, as determined by adjustmentof the stud 39, has been built up in the output chamber 31, thediaphragm 32 will have been raised to a point where the spring 35 isinelfective to decenter the piston 2 sutficiently to cause furtherliquid to be pumped into the output chamber. In other words, the pistonremains in a substantially centered relation to the electro-magnet 3with little or no vibratory movement.

When liquid is withdrawn through the output fitting 42, the diaphragm 32is thereby permitted to move downwardly under the force of the spring37, thus applying pressure through the spring 35 to the piston 2,causing it to vibrate with an amplitude corresponding to the volume ofliquid withdrawn from the output chamber.

Although but two embodiments of the invention have been shown anddescribed in detail it will be understood that other embodiments arepossible and changes may be made in thedesign and arrangement of theparts Without departing from the spirit of the invention.

I claim:

1. In an electromagnetic reciprocating pump a nonmagnetic cylinder, ahollow magnetic piston slidably mounted therein, an electromagnetsurrounding the cylinder and piston, a source of continuously pulsatingcurrent for energizing the electro-magnet to cause a continuousreciprocatory movement of the piston, a casing enclosing the cylinderand electromagnet and providing input and output chambers at theopposite ends of the cylinder, yielding means continuously urging thepiston away from its centered relation with respect to the electromagnettoward the input end of the cylinder, valve means for preventingbackward flow of liquid through the cylinder, and means for varying theforce of said yielding means on the piston responsive to variations inflow from the output chamber.

2. An electromagnetic pump as set forth in claim 1 including furthermeans for limiting the decentering movement of the piston responsive tosaid yielding means.

3. An electromagnetic pump as set forth in claim 2 in which the yieldingmeans is in the form of a compression spring, and the means for varyingthe force of the yielding means comprises a buoyant member floating inthe output chamber of the pump and resting on said spring.

4. An electromagnetic pump as set forth in claim 3 including furtheradjustable means for applying a yielding pressure on said floatingmember.

5. An electromagnetic pump as set forth in claim 1 in which saidyielding means is in the form of a compression spring, and the means forvarying the force of said yielding means comprises a flexible diaphragmforming one Wall of the output chamber of the pump, and yielding meansfor moving the diaphragm to apply pressure to said spring.

6. An electromagnet as set forth in claim 5 including means accessiblefrom the exterior of the pump to vary the pressure of said yieldingmeans on the diaphragm.

References Cited in the file of this patent UNITED STATES PATENTS1,631,984 Redmond June 14, 1927 FOREIGN PATENTS 344,843 Great BritainMar. 2, 1931

